Randomized clinical trials regarding management of atherosclerotic renovascular disease.

Prospective randomized clinical trials that support operative correction of atherosclerotic renovascular disease or catheter-based intervention compared with optimal medical management are lacking. Despite various limitations in study design, each of the five randomized trials reported to date had demonstrated no apparent benefit for renal artery intervention compared with medical management. Three ongoing randomized trials promise to provide additional data and the results of these latter studies will likely dictate future reimbursement through the Centers for Medicare and Medicaid Services.

A vascular disease educational program in the preclinical years of medical school increases student interest in vascular disease.

BACKGROUND: New training paradigms in vascular surgery necessitate medical student interest in vascular disease. We examined the effects of incorporation of a vascular disease educational program during the second year of the medical school curriculum on student acquisition of knowledge and interest in the treatment of vascular disease. METHODS: We developed and administered a new educational program on vascular disease and delivered the program to all second-year medical students. The new program encompassed 9 didactic hours, including 7 traditional lecture hours and 2 hours of problem-based learning. After completing the program, students were surveyed regarding vascular disease-specific knowledge, interest in treating vascular disease, and career choices. Third-year students who were not exposed to the program were surveyed as a control group. We recorded the voluntary student enrollment in the vascular and endovascular surgery rotation during the following academic year. Voluntary enrollment of the students exposed to the vascular disease education program was compared with enrollment for the previous 8 years. RESULTS: Before the introduction of the new educational program, 946 total lecture hours were delivered to first- and second-year medical students, comprising 490 hours (52%) given by nonsurgeon physicians, 445 (47%) by nonphysicians, and 11 (1%) by surgeons. Survey response rate was 93% (112 of 121) for second-year students and 95% (39 of 41) for third-year students. After the vascular disease program, second-year students answered 7.1 +/- 1.4 of 9 vascular disease questions correctly, whereas unexposed third-year students answered 7.2 +/- 1.7 questions correctly (P = .96). Most second-year medical students described a "somewhat" or "much greater" interest in the medical (63%), procedural (59%), and overall (63%) management of vascular disease after exposure to the program. Most also had a "somewhat" or "much greater" interest in a vascular medicine (64%) or vascular and endovascular surgery (60%) rotation. Enrollment in the vascular surgery third-year clerkship increased significantly to a mean of 3.0 students/month from 1.16 students/month in the prior year (P = .0032, postintervention year vs 8 prior years). CONCLUSION: A vascular disease educational program administered to second-year medical students increases interest in vascular disease and interest in further training. The increased interest translates to greater student enrollment in the vascular surgery clerkship in the subsequent academic year.

Accuracy of duplex sonography scans after renal artery stenting.

PURPOSE: Reports of duplex sonography scan criteria for recurrent renal arterial (RA) stenosis after endoluminal stenting have suggested that criteria for native arteries may overestimate recurrent disease. This retrospective report examines the utility of renal duplex sonography (RDS) scans to define the presence of significant (ie, ≥ 60%) renovascular disease (RVD) after percutaneous angioplasty and endoluminal stenting (PTAS). METHODS: Demographic, duplex, and angiographic data were reviewed and compared. RDS was obtained. Peak systolic velocities (PSV) were obtained after PTAS from multiple sites along the main RA from both anterior and flank approaches. Comparable images from digital subtraction angiography were independently examined for restenosis. Percent diameter stenosis was determined from the site of maximal stenosis compared with the normal RA distal to the stent. Sensitivity and specificity were estimated and 95% confidence intervals (CIs) were computed after adjusting for within patient "clustering" of observations applying native RA RDS criteria using angiography as the gold standard. Receiver operating characteristic (ROC) curves were used to estimate the optimal RDS values for recurrent stenosis. RESULTS: From October 2003 to June 2009, 49 patients had angiographic imaging after PTAS. There were 30 patients (18 women, 12 men; mean age, 71 ± 9 years) provided technically adequate paired angiographic and RDS assessment after PTAS for 66 RAs. Paired analysis was performed for 23 RAs after primary PTAS and 43 RAs after secondary treatment. The prevalence of significant restenosis was 35% (23 of 66 RAs). RAs with greater than 60% diameter restenosis had higher peak systolic velocity (PSV) compared to those without (2.48 ± 1.15 millisecond vs 1.44 ± 0.58 millisecond; P < .001). Compared to angiography, RA-PSV ≥ 1.8 millisecond with distal RA turbulence demonstrated a sensitivity of 73% (95% CI, 54%, 91%), specificity of 80% (95% CI, 67%, 93%), and an overall accuracy of 77% (95% CI, 67%, 88%) with a positive predictive value of 64% (95% CI, 46%, 82%). Optimal RDS value estimated by ROC curve resulted in RA-PSV of 2.5 millisecond which was associated with a sensitivity of 59% (95% CI, 36%, 82%), specificity of 95% (95% CI, 89%, 100%), an accuracy of 83% (95% CI, 74%, 92%), and a positive predictive value of 87% (95% CI, 68%, 100%). CONCLUSION: Renal duplex sonography has utility to detect significant restenosis after PTAS. RDS criteria for significant native RA stenosis compare favorably with optimal RDS criteria for restenosis estimated by ROC curves.

Associations between renal duplex parameters and adverse cardiovascular events in the elderly: a prospective cohort study.

BACKGROUND: Atherosclerotic renovascular disease is associated with an increased risk of cardiovascular disease (CVD) events. This study examines associations between Doppler-derived parameters from the renal artery and renal parenchyma and all-cause mortality and fatal and nonfatal CVD events in a cohort of elderly Americans. STUDY DESIGN: Cohort study. SETTING: A subset of participants from the Cardiovascular Health Study (CHS). Through an ancillary study, 870 (70% recruitment) Forsyth County, NC, CHS participants consented to undergo renal duplex sonography to define the prevalence of renovascular disease in the elderly, resulting in 726 (36% men; mean age, 77 years) technically adequate complete studies included in this investigation. PREDICTOR: Renal duplex sonography-derived Doppler signals from the main renal arteries and renal parenchyma. Spectral analysis from Doppler-shifted frequencies and angle of insonation were used to estimate renal artery peak systolic and end diastolic velocity (both in meters per second). Color Doppler was used to identify the corticomedullary junction. Using a 3-mm Doppler sample, the parenchymal peak systolic and end diastolic frequency shift (both in kilohertz) were obtained. Resistive index was calculated as (1 - [end diastolic frequency shift/peak systolic frequency shift]) using Doppler samples from the hilar arteries of the left or right kidney with the higher main renal artery peak systolic velocity. OUTCOMES & MEASUREMENTS: Proportional hazard regression analysis was used to determine associations between renal duplex sonography-derived Doppler signals and CVD events and all-cause mortality adjusted for accepted cardiovascular risk factors. Index CVD outcomes were defined as coronary events (angina, myocardial infarction, and coronary artery bypass grafting/percutaneous coronary intervention), cerebrovascular events (stroke or transient ischemic attack), and any CVD event (angina, congestive heart failure, myocardial infarction, stroke, transient ischemic attack, and coronary artery bypass grafting [CABG]/percutaneous transluminal coronary intervention [PTCI]). RESULTS: During follow-up, 221 deaths (31%), 229 CVD events (32%), 122 coronary events (17%), and 92 cerebrovascular events (13%) were observed. Renal duplex sonography-derived Doppler signals from the renal parenchyma were associated independently with all-cause mortality and CVD outcomes. In particular, increased parenchymal end diastolic frequency shift was associated significantly with any CVD event (HR, 0.73; 95% CI, 0.62-0.87; P < 0.001). Marginally significant associations were observed between increases in parenchymal end diastolic frequency shift and decreased risk of death (HR, 0.86; 95% CI, 0.73-1.00; P = 0.06) and decreased risk of cerebrovascular events (HR, 0.78; 95% CI, 0.61-1.01; P = 0.06). Parenchymal end diastolic frequency shift was not significantly predictive of coronary events (HR, 0.84; 95% CI, 0.67-1.06; P = 0.1). LIMITATIONS: CHS participants showed a "healthy cohort" effect that may underestimate the rate of CVD events in the general population. CONCLUSION: Renal duplex sonographic Doppler signals from the renal parenchyma showed significant associations with subsequent CVD events after controlling for other significant risk factors. In particular, a standard deviation increase in parenchymal end diastolic frequency shift was associated with 27% risk reduction in any CVD event.

Outcome of patients with sleep complaints and normal polysomnograms.

STUDY OBJECTIVE: To determine the outcome in patients with sleep complaints and normal polysomnograms (PSG). BACKGROUND: PSG is used in the evaluation of persons with sleep complaints. There is a small amount of literature available on patients with sleep complaints and normal PSGs. METHODS: PSGs interpreted as normal at the sleep laboratory at Wake Forest University Baptist Medical Center over a 3-year period were considered for inclusion. All PSG requests were screened for appropriateness. Follow-up data were obtained by structured telephone interview (within a period of 5 months of PSG) and chart review. This interview requested: (1) main sleep complaint, (2) diagnosis given by the ordering physician, (3) treatment for the sleep complaint, (4) further studies, and (5) overall satisfaction. RESULTS: Forty-six patients were identified with a normal PSG, and 27 (58%) were successfully contacted for the telephone interview. Of these 27 patients, 8 were men and 19 were women. Fifty-two percent of patients were not given a diagnosis by the referring physician after their normal PSG to explain their sleep symptoms. Eight patients (29%) were offered treatment for their sleep complaints despite their normal PSGs. Twenty patients (74%) reported no change in their sleep quality since the PSG. Most patients (66%) did not find the PSG helpful. CONCLUSIONS: The majority of patients with sleep complaints and normal PSG were not given a clear diagnosis by the referring physician, and sleep complaints persist after a normal PSG. Further evaluation by a sleep specialist may be appropriate.

Laparoscopic radiofrequency ablation of the liver in proximity to major vasculature: effect of the Pringle maneuver.

BACKGROUND AND OBJECTIVES: The Pringle maneuver has been shown to increase ablation size during radiofrequency ablation (RFA). Efficacy of laparoscopic Pringle in proximity to major vasculature has not been well described. Laparoscopic RFA was performed in proximity to major hepatic vessels to examine effects of the Pringle on ablation size and vascular damage. METHODS: Laparoscopic RFA was performed in 10 pigs. Each underwent ablation of a peripheral site, and sites adjacent to the portal and hepatic veins. Ultrasound was used to position the RFA adjacent to vascular structures. US flow characteristics verified occlusion of blood flow. Five pigs underwent laparoscopic RFA with Pringle and five underwent laparoscopic RFA alone. Animals were then sacrificed for gross and microscopic evaluation. RESULTS: Peripheral, hepatic, and portal vein ablations showed no significant differences in volume between non-Pringle and Pringle lesions, though the median ablation volume for the peripheral site in the Pringle group was approximately twice that of the non-Pringle group. Pringle group overall median time to target temperature was significantly shorter (P = 0.047). Histologic examination revealed no evidence of endothelial damage or thermal-induced intravascular thrombosis of the hepatic or portal veins. CONCLUSIONS: Laparoscopic RFA with Pringle in proximity to major vascular structures does not significantly increase ablation size, or cause acute vascular damage. Further studies are necessary to determine the utility of the Pringle in proximity to major intrahepatic blood vessels.